A

SEMINAR REPORT ON

“Study of a Multistory Building's Diagrid Structure”

SUBMITTED IN THE PARTIAL FULFILLMENT OF THE REQUIREMENT FOR THE
DEGREE OF

MASTER OF CIVIL ENGINEERING

(STRUCTURES)
OF THE

SAVITRIBAI PHULE PUNE UNIVERSITY

SUBMITTED BY,

Mr. Shekhar B. Ghadge

Seat No.:-

UNDER THE GUIDANCE OF,

Dr. V. V. Shelar

DEPARTMENT OF CIVIL ENGINEERING

TRINITY COLLEGE OF ENGINEERING AND RESEARCH

KONDHAWA - SASWAD ROAD, BOPDEV GHAT, PUNE-411048

2024-2025
 KJ’s EDUCATIONAL INSTITUTE’S
TRINITY COLLEGE OF ENGINEERING AND RESEARCH, PUNE
DEPARTMENT OF CIVIL ENGINEERING

C ERTIFICATE
This is to certify that the following student have satisfactory carried out the Seminar-II
entitled “Study of a Multistory Building's Diagrid Structure”. This work is being
submitted for the award of degree of Masters in Structural Engineering. It is submitted in the
partial fulfilment of the prescribed syllabus of Savitribai Phule Pune University, in the
academic year 2024-2025.

Seat No Name of Student

Mr. Shekhr B. Ghadge

Dr. V.V.Shelar Dr. V.V.Shelar

Seminar Guide (PG CO-Coordinator)

HOD External Examiner Dr. A. B. Auti

Civil Engineering (Principal)
 ACKNOWLEDGEMENT

I would like to express sincere gratitude to my guide Dr. V. V. Shelar for his constant
encouragement, support, help and advice during the course of my Seminar II am very much
thankful to him for his invaluable suggestions and guidance.
I would also like to thank all teachers & Dr. V.V. Shelar (PG Co-ordinator) for his
valuable suggestions. While submitting report avail the opportunity to express deepest
gratitude towards my friends and seniors and all who have helped to complete the task
completely and successfully.
I would also like to thank HOD of Civil Engineering Department for his valuable
suggestions and I acknowledge with thanks, the Staff of Civil engineering department and
central library.
I would like to thank honorable Mr. K. J. Jadhav, founder president of KJEI’s Pune
and Dr. A. B. Auti, Principal of K.J.E.I’s Trinity College of Engineering and Research,
Pune for giving me chance for doing work.
Finally, I am thankful to those who directly and indirectly helped me and supported
me to complete this work.

Shekhar Babaso Ghadge

 ABSTRACT

The diagrid structures are buildings with diagonal grids in the periphery at a particular
angle and in modules across the height of the building. construction of multi‐storey building
is rapidly increasing throughout the world. Recently the diagrid structural system has been
widely used for tall buildings due to the structural efficiency and aesthetic potential provided
by the unique geometric configuration of the system.These days the latest trend of technology
in diagrid structures is evolving.
Diagrid is an exterior structural system in which all perimeter vertical columns are eliminated
and consists of diagonal grids in the periphery at a particular angle and in modules across the height
of the building. The current trends of construction industry demand tall and lighter structures. These
tall structures are very sensitive to Lateral loads induced by wind or earthquake along with
gravitational loading. With the increase in height of the building, the lateral load resisting system
becomes more vital than the structural system that resists the gravitational loads. Diagrid system is an
innovative technology which promises better lateral load efficiency and is widely used now a days in
the design of tall buildings because of its inherent structural efficiency as well as aesthetic potential
provided by the unique geometric configuration of the system.
Auxiliary damping systems controlling building motion are also discussed. Further,
contemporary “out-of-the-box” architectural design trends, such as aerodynamic and twisted forms,
which directly or indirectly affect the structural performance of tall buildings, are reviewed. Finally,
the future of structural developments in tall buildings is envisioned briefly. Tall building
developments have been rapidly increasing worldwide. the evolution of tall building’s structural
systems and the technological driving force behind tall building developments. For the primary
structural systems, a new classification – interior structures and exterior structures – is presented.
The main objective was to determine the optimum module size of diagrid. In the modern age,
architects and engineers are developing cities vertically due to the decrease in availability of free land,
increase in land prices, and the widespread urbanization. However, there are practical constraints to
bound the vertical limits of skyscrapers. Therefore, it is essential for architecture and structural
engineering to understand the study of structural systems for tall buildings.
 CONTENTS
Sr. No Description Page No
1 Title page i
2 Certificate of Seminar ii
3 Acknowledgement iii
4 Abstract iv
5 Content vi
6 List of Figures vii
7 List of Tables viii
8 List of Graphs viii
Sr.No Contents Page No
1 INTRODUCTION 1-4
1.1 General 1
1.2 Diagrid System 1
1.3 Diagrid Angle 1
1.4 The Triangular Diagrid Module 2
1.4.1 Introduction 2
1.4.2 Module Geometry 3
1.5 Problem Statement 4
1.6 Objectives 4
1.7 Scope of Project Work 4
2 LITERATURE REVIEW 5
3 METHODOLOGY AND DATA COLLECTION 8
3.1 Geometry and Structural Data 8
3.2 Load Combination Of Wind And Seismic Load 8
3.3 Wind Design 9
3.4 Seismic Design 9
3.5 Models Generation 9
4 MERITS AND DEMERITS OF DIAGRIDS 12
5 DESIGN AND CONSTRUCTION OF DIAGRID NODES 13

5.1 Materials Used For Diagrid 13

5.2 Diagrid Node Design 15
5.2.1Node Construction For Diagrid Structures 16
5.2.2 Erection of Diagrid Nodes
17

6 CASE STUDY 18
7 RESULTS 21
8 CONCLUSION 29
REFERENCES 30
 LIST OF FIGURES
Sr. No. Description Page No.
1.1 Show in Diagrid Structure 2
1.2 8 Storey diagrid with 60 degree diagonal angle 2
5.1 Load Path at Node 5
5.2 Diagrid Node Design 15
5.3 Node detail for the Hearst Tower 16
A Diagrid node after fabrication
5.4 17
5.5 Construction Plan of a Diagrid 17
5.6 Diagrid Erection Process 17
6.1 i-Lab Building, Hyderabad 18
6.2 Interior view of i-Lab Building 18

LIST OF TABLE

Sr.No. Description Page No.

1 Seismic Parameters 9
2 Storey module of diagrid angel 10
3 Preliminary sizes in mm for member G+24 Storey 10
4 Preliminary sizes in mm for member G+36 Storey 10
5 Preliminary sizes in mm for member G+48 Storey 11
6 Preliminary sizes in mm for member G+60 Storey 11
 Study of a Multistory Building's Diagrid Structure

Chapter 1

Introduction

1.1 General
The development and growth of tall buildings around the world in populated
cities is increasing day by day. It is due to continuous urban sprawl, availability of
more rental areas with less environmental damage, constructional cost efficiency and
the need to preserve the agricultural land. Diagrid – Diagonalised grid structures is one
of the emerging innovative concepts to design tall buildings. Diagrid not only gives
more stiffness but also resist the lateral forces (Due to wind and seismic) and gravity
load by axial action. It is a particular form of space truss consisting of perimeter grid
made up of triangular structural system. Diagrid- a word formed by combination of
“diagonal” and “grid” designated Diagrid as a totally new trend.
Diagrid is a particular form of space truss consisting of perimeter grid made up of
series of triangular module. This module can also be of diamond shaped. The
important point for a diagrid structure system is selection of material for the structure.
The materials available for the construction of diagrid are:-
1. Steel
2. Concrete
3. Timber

1.2 Diagrid System

A diagrid structure is a type of structural system consisting of diagonal grids
connected through horizontal rings which create an elegant and redundant structure
that is especially efficient for high-rise buildings. A diagrid structure is different from
braced frame systems, since diagonals as main structural elements participate in
carrying gravity load in addition to carrying lateral load due to their triangulated
configuration, which eliminates the need for vertical columns. The column free
structure of a diagrid system offers several advantages such as high architectural
flexibility and elegancy, and enormous day lighting due to its large free surface.

1.3 Diagrid Angle

Structural design of diagrid structure is greatly influenced by the angle of
diagonals. With the deviation of angle of diagonals from optimum condition, not only
the required amount of steel increases significantly but also storey drift of structure,

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 Study of a Multistory Building's Diagrid Structure

storey shear and top storey displacement changes. Therefore, it is very necessary for an
Engineer to obtain the optimum angle of diagonals in diagrid structure in order to
obtain a safe structural design of diagrid. For maximum bending rigidity, the angle
made by column should be 90° and for maximum shear rigidity, it is 35°. It is expected
that optimum angle of diagrid falls in this range. bending beams whereas short
buildings with low aspect ratio behave like shear beams. Thus, it is expected that,
increase in building height increases the optimal angle of diagonals.

Fig 1.1 Show in Diagrid Structure

1.4 The Triangular Diagrid Module

1.4.1 Introduction
Diagrid structure is modeled as a beam, and subdivided longitudinally into modules
according to this repetitive diagonal pattern. Each Diagrid module is defined by a single
level of diagonals that extend over ‘n’ stories.

Fig 1.2 8 Storey diagrid with 60 degree diagonal angle

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1.4.2 Module Geometry

Diagrid structures, like all the tubular configurations, utilize the overall
building plan dimension for counteracting overturning moment and providing flexural
rigidity through axial action in the diagonals, which acts as inclined columns; however,
this potential bending efficiency of tubular configuration is never fully achievable, due
to shear deformations that arise in the building “webs”; with this regard, diagrid
systems, which provide shear resistance and rigidity by means of axial action in the
diagonal members, rather than bending moment in beams and columns, allows for a
nearly full exploitation of the theoretical bending resistance. Being the diagrid a
triangulated configuration of structural members, the geometry of the single module
plays a major role in the internal axial force distribution, as well as in conferring global
shear and bending rigidity to the building structure. While a module angle equal to 35°
ensures the maximum shear rigidity to the diagrid system, the maximum engagement
of diagonal members for bending stiffness corresponds to an angle value of 90°, i.e.
vertical columns. Thus in diagrid systems, where vertical columns are completely
eliminated and both shear and bending stiffness must be provided by diagonals, a
balance between this two conflicting requirements should be searched for defining the
optimal angle of the diagrid module. Usually Isosceles triangular geometry is used.

Optimal Angle:
As in the diagrids, diagonals carry both shear and moment. Thus, the optimal
angle of diagonals is highly dependent upon the building height. Since the optimal
angle of the columns for maximum bending rigidity is 90 degrees and that of the
diagonals for maximum shear rigidity is about 35 degrees, it is expected that the
optimal angle of diagonal members for diagrid structures will fall between these angles
and as the building height increases, the optimal angle also increases. Usually adopted
range is 60 -70 degree.

Module Dimensions:

 Height of the module: It depends on the number of stories stacked per module.
Usually 2 – 6 stories are stacked per diagrid with average floor height varying from
3.5 -4.15 m on an average.
 Base of the module: It depends on the height and optimal angle (apex angle) of the
diagrid.

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1.5 Problem Statement

The problem statement for this project is the study of the behaviour of multistory
building’s diagrid structure. The specific objective of the study is to study the concept of
diagrid structural system. The purpose of this study is to study the concept of diagrid
structural system. The findings of the study have a form of a space truss which is effective
in reducing shear deformation, as they carry the lateral load by an axial action of diagonal

members.

1.6 Objectives
i) The Main objective of this study is to understand the concept of diagrid structural
system.
ii) To understand the analysis and design methodology of diagrid structure using
STAAD.Pro v8i ss5 software. 
iii) To determine the various optimum angle and various storey for diagrid system. 
iv) Analysis of building wind analysis. 
v) Analysis of building frames considering seismic analysis. 
vi) Comparison between conventional building and diagrid building.

1.7 Scope of Project Work

Higher storey buildings can be studied in R.C.C symmetrical building for diagrid
structure. Asymmetrical building with different angel study for diagrid structure. Study
with and without outer column for diagrid structure. Steel building can also studies diagrid
structures. Comparative study braced tube system and diagrid structures.

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 Study of a Multistory Building's Diagrid Structure

Chapter 2
Literature Review

Anjali Bhimrao Patil, Prof. Dr.P.P.Saklecha, Prof. V.A.Kalmegh et.al. “ Study on

diagrid structure of Multistorey building” (2022)
In this paper work describes a stiffness-based design process for estimating preliminary
member sizes in r.c.c. diagrid structures for tall buildings. A G+24, G+36, G+48, G+60
story RCC structure with a plan dimension of 18 m 18 m located in Surat is being
examined for wind and seismic study. STAAD. Pro programme is used for structural
member modelling and analysis. All structural components are developed in accordance
with IS 456:2000, and seismic force load combinations are taken into account in
accordance with IS1893(Part 1): 2002. Analysis findings are compared in terms of beam
displacement, Storey Drift, and Bending Moment. This results in a more cost-effective
diagrid structure design as compared to a traditional structure.

Vyankatesh Holambe, S. G. Ban, Syed Shafahaduddin Quadri et.al.“ Literature

Review on Structural Role of Diagrids in High- Rise Structure under Dynamic
Forces” (2022)
The main aim of this literature review is to find suitable research gaps on topic related
to diagrids. This review summarizes various research works achieved by diagrid structural
system for high rise structures and confirms that the structure has larger lateral stiffness
and good seismic performance. Based on the favorable performance of concrete‐filled
steel tubes, this research work advises the use of diagrid structural systems for tall
structures. Most of the researchers concluded their study considering structural
performance and stability which depends on structural Forces, Moments, Displacement,
Storey Drifts, Natural Frequency and Base Shear.

Ravi Sorathiya, Asst. Prof. Pradeep Pandey et.al. “Study on diagrid structure of
multistorey building” (2017)
This paper presents a stiffness-based design methodology for determining preliminary
member sizes of r.c.c diagrid structures for tall buildings. A G+24, G+36,G+48,G+60
storey RCC building with plan size 18 m × 18 m located in surat wind and seismic is
considered for analysis. STAAD.Pro software is used for modelling and analysis of
structural members. All structural members are designed as per IS 456:2000 and load

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 Study of a Multistory Building's Diagrid Structure

combinations of seismic forces are considered as per IS 1893(Part 1): 2002. Comparison of
analysis results in terms of beam displacement, Storey Drift, Bending Moment. This cause
economical design of diagrid structure compared to conventional structure.

Kyoung Sun Moon et.al. “ Diagrid Systems for Structural Design of Complex Shaped
Tall Buildings”(2016)
This paper studies structural performance of diagrid systems employed for complex-
shaped tall buildings.Twisted, tilted, tapered and freeform tall buildings are designed with
diagrid structures, and their structural performances are investigated. This paper studied
lateral performance of diagrid structures employed for these complex-shaped tall
buildings of various form categories.

Saket Yadav, Dr. Vivek Garg et.al. “ Advantage of Steel Diagrid Building Over
Conventional Building” (2015)
In this study, the structural response of conventional and diagrid building is
investigated to evaluate the structural benefits of diagrid system. A regular G+15 storey
steel building with a plan size of 18 m x 18 m, located in a seismic zone V is analysed and
designed by STAAD Pro. Software. All structural members are designed as per Indian
standard for general construction in steel (IS 800:2007) and the seismic forces are
considered as per Indian codal provision for earthquake resistant design of structure (IS
1893 (Part 1): 2002). In diagrid structure, the major portion of lateral load is taken by the
external diagonal members, which in turn releases the forces in other members of the
structure. The use of diagrids significantly decreases the maximum shear force and bending
moment in internal and perimeter beams.

Raghunath .D. Deshpande, Sadanand M. Pati, Subramanya Ratan et.al. “Analysis

and comparison of diagrid and conventional Structural system” (2015)
The main objective of the project is to compare the efficiencies of conventional and diagrid
structural patterns for tall structure and this is possible only when both the structures share
the same design aspects. Since the storey height of 3m was adopted in conventional
rectangular pattern, the same is maintained for the diagrid structure. Due to inclined
columns lateral loads are resisted by axial action of the diagonal compared to bending of
vertical columns in framed tube structure. Diagrid structures generally do not require core

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because lateral shear can be carried by the diagonals on the periphery of building.

Sree Harsha J, K Raghu, G Narayana et.al. “Analysis of tall buildings for desired
angle of diagrids” (2015)
In this present study the non linear analysis is carried out for the considered diagrid
structural system. The comparison of analyzed results in terms of top storey displacement,
time period, storey shears and mode shapes is presented.in order to determine the optimal
uniform angle for each structure with a different height and to investigate the structural
potential of diagrids with changing angles The comparison of 24-storey diagrid structural
system with different uniform angles is presented here.. The 24 storey diagrid structural
system with different angles are modelled and analyzed by using Etabs Software. Now a
day the Non linear analysis is essential for a tall building.

Shahana E, Aswathy S Kumar et.al. “ Comparative Study of Diagrid Structures with

and without Corner Columns” (2015)
In present work, concrete diagrid structures with and without corner columns were
analysed and compared. Due to inclined columns, lateral loads are resisted by axial action
of the diagonal in diagrid structure compared to buckling of vertical columns. Comparison
of analysis results in terms of storey drift, lateral displacement, bending moment, shear
forces and axial forces are presented. In diagrid structure, the major portion of lateral load
is taken by external diagonal members which in turn release the lateral load in inner
columns. Thus, the study can be concluded as the behaviour of structure without corner
column is more effective than with corner columns..

Khushbu Jania , Paresh V. Patelb et.al. “Analysis and Design of Diagrid Structural
System for High Rise Steel Buildings” (2013)
In this paper, analysis and design of 36 storey diagrid steel building is presented in detail.
A regular floor plan of 36 m × 36 m size is considered. ETABS software is used for
modeling and analysis of structure. All structural members are designed using IS 800:2007
considering all load combinations. Load distribution in diagrid system is also studied for 36
storey building. Also, the analysis and design results of 50, 60, 70 and 80 storey diagrid
structures are presented.

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Chapter 3
Methodology and Data Collection
The design methodology is applied to a set of diagrid structures G+24, G+36, G+48 and
G+60 stories tall, The diagrid structure of each storey height is designed with diagonals of
various uniform angles as well as diagonals of gradually changing angles over the building
height in order to determine the optimal grid geometry of the structure within a certain
height range. The building’s typical plan dimensions are 18x 18 meters with typical storey
heights of 3 meters. The structures are assumed to be in Surat.

3.1 Geometry And Structural Data

(1) Plan dimension-18x18 m
(2) Storey height-3 m
(3) Diagrid angel-57º,63º,69º,73º
(4) No. of storey- G+24, G+36, G+48 and G+60
(5) Diagrid storey module-2,3,4 and 6 storey
(6) The dead load taken -8.75 KN/m
Floor finish-2 KN/m²
(7) Live load-floor finish-2.5 KN/m²
(8) Slab thickness-200 mm
(9) Support- Pinned support
(10) Characteristic strength of concrete: 30 N/mm2
(11) Characteristic strength of steel: 415 N/mm2

3.2 Load Combination Of Wind And Seismic Load

(1) 1.5(DL+LL)
(2) 1.5(DL+WLX+VE) and 1.5(DL+ELX+VE)
(3) 1.5(DL-WLZ-VE) and 1.5(DL-ELZ-VE)
(4) 1.5(DL+LL+WLX+VE) and 1.5(DL+LL+ELX+VE)
(5) 1.5(DL+LL-WLZ-VE) and 1.5(DL+LL-ELZ-VE)
(6) 1.2(DL+LL-WLX-VE) and 1.2(DL+LL-ELX-VE)
(7) 1.2(DL+LL+WLZ+VE) and 1.2(DL+LL+ELZ+VE)
(8) 0.9(DL+LL+WLX+VE) and0.9(DL+LL+ELX+VE)
(9) 0.9(DL+LL-WLZ-VE)and 0.9(DL+LL-ELZ-VE)

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 Study of a Multistory Building's Diagrid Structure

3.3 Wind Design

Vz = vb kl k2 k3
Vz = design wind speed at any height z in m/s;
k1 = probability factor (risk coefficient )
k2 = terrain, height and structure size factor and
k3 = topography factor

3.4 Seismic Design

Ah= Z I Sa/2 R g
Z=zone factor
I= importance factor depending upon the functional use of the structures, characterized by
hazardous consequences of its failure, post-earthquake functional needs, historical value,
or economic importance
R= Response reduction factor, depending on the perceived seismic damage performance of
the structure, characterised by ductile or brittle deformations. However, the ratio
(I/R)shall not be greater than 1.0
Sa/g= Average response acceleration coefficient
G
NO SEISMIC PARAMETERS B
1 Zone factor(zone-3) 0.16
2 Type of soil Medium
3 Importance factor 1
4 Response reduction factor 5(SMRF)

L3.
Table No.1 Seismic Parameters
3.5 Models Generation
There are four different story of building analyzed
(1) G+24 Storey
(2) G+36 Storey
(3) G+48 Storey
(4) G+60 Storey

And in each storey there are five types model generation

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 Study of a Multistory Building's Diagrid Structure

(1) 57° diagrid angel

(2) 63° diagrid angel
(3) 69° diagrid angel
(4) 73° diagrid angel
(5) Conventional building

And all these models are analyzed for wind analysis IS code 875(PART 3):1987 and
seismic analysis IS 1893(part1):2002
fff Storey module Diagrid Angel Storey
TTa 2 Storey 57° G+24 G+36 \ G+48 G+60
3 Storey 63°
ble 4 Storey 69°
No. 6 storey 73°
2 Storey module of diagrid angel

Storey Element size in mm

G+24 Storey Beams Column Diagrid
450 X 800 750 X 750 650 X 650
450 X 600 650 X 650 -
300 X 600 600 X 600 -

vvvvvTable No. 3 Preliminary sizes in mm for member G+24 Storey

Storey Element size in mm

G+36 Storey Beam Column Diagrid
450 X 450 800 X 800 650 X 650
450 X 600 750 X 750 -
300 X 600 700 X 700 -
300 X 450 650 X 650 -
300 X 400 600 X 600 -

Ssssssss Table No. 4 Preliminary sizes in mm for member G+36 Storey

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Storey Elements in mm
G+48 Storey Beam Column Diagrid
450 X 800 900 X 900 650 X 650
450 X 600 850 X 850 -
300 X 600 800 X 800 -
300 X 450 750 X 750 -
300 X 400 700 X 700 -
300 X 350 650 X 650 -

Ssssssss Table No. 5 Preliminary sizes in mm for member G+48 Storey

Storey Elements in mm
G+60 Storey Beam Column Diagrid
450 X 800 950 X 950 650 X 650
450 X 600 900 X 900 -
350 X 600 850 X 850 -
300 X 600 800 X 800 -
300 X 450 750 X 750 -
300 X 400 700 X 700 -
300 X 350 650 X 650 -

sssssssssTable No.6 Preliminary sizes in mm for member G+60 Storey

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Chapter 4
Merits and Demerits of Diagrids

Merits of diagrids:

Some major benefits of using Diagrids in structures are discussed below.

1) The Diagrid structures have mostly column free exterior and interior, hence free and
clear, unique floor plans are Possible.
2) The Glass facades and dearth of interior columns allow generous amounts of day
lighting into the structure.
3) The use of Diagrids results in roughly 1/5th reduction in steel as compared to Braced
frame structures.
4) The construction techniques involved are simple, yet they need to be perfect.
5) The Diagrids makes maximum exploitation of the structural Material.
6) The diagrid Structures are aesthetically dominant and expressive.
7) Redundancy in the DiaGrid design is obvious. It is this redundancy then that can
transfer load from a failed portion of the structure to another. Skyscraper structural
failure, as it is such an important/ prominent topic, can be minimized in a DiaGrid
design A DiaGrid has better ability to redistribute load than a Moment Frame
skyscraper. Thus creating a deserved appeal for the DiaGrid in today’s landscape of
building.

Demerits of Diagrids:
Some demerits of using Diagrids are mentioned below:

1) As of yet, the Diagrid Construction techniques are not thoroughly explored.

2) Lack of availability of skilled workers . Construction crews have little or no experience
creating a DiaGrid skyscraper.
3) The DiaGrid can dominate aesthetically, which can be an issue depending upon design
intent.
4) It is hard to design windows that create a regular language from floor to floor.
5) The DiaGrid is heavy-handed if not executed properly.

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Chapter 5

Design and Construction of Diagrid Nodes

5.1 Materials Used For Diagrids:

Material selection for a Diagrid construction is based on the following factors .
They are:

a) Unit weight of the material.

b) Availability of the material.
c) Lead Time.
d) Erection Time.
e) Flexibility.
f) Durability.
g) Labor cost.
h) Fire resistance.

The basic materials used in Diagrid construction are Steel, Concrete and Wood. The
relative merits and demerits of using them are discussed below.

Steel:
Steel is by far the most popular material for Diagrid constructions. The typical steel
sections used are Wide flanges, Rectangular HSS and Round HSS.
Steel Wide Flanges:
Advantages- The weight and Size of wide flanges are optimized to resist the high bending
loads many of the members experience. Thus use of wide flanges results in reduced
structure weight and flexibility of size. The sections can be prefabricated in multi-panel
sections, allowing quick erection by crane, reducing labor costs in the field.

Disadvantages- Pre-fabrication of the Diagrid sections takes a longer lead time.

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Rectangular and Round HSS:

Advantages- As with wide flanges, HSS sections can be prefabricated in multi-panel

sections, allowing quick erection time, also reducing labor costs in the field.

Disadvantages- Use of HSS sections will need a change in floor layouts as the beams will
need to frame into the node points. This reduces the floor flexibility and efficiency.

Concrete:
Concrete is another widespread material for Diagrid constructions. It is used both in
Precast and Cast-in-situ forms.

Precast concrete:

Advantages-The flexibility of precast sections allows them to fit to the complex building
geometries. Concrete also offers extreme safety against structural fire damage.

Disadvantages- The use of Concrete increases the dead load on the foundations,
deflections of long spans, etc. Creep in concrete is also an issue. -in-situ Concrete: Under
an Efficient material management system, cast-in-situ concrete is the best material in
terms of material cost. Lead time is virtually nothing as cast-in-situ is available on
demand.
.
Timber:
Timber is the least popular material for Diagrid constructions.

Advantages- Multi-panel sections can reduce erection time and labor cost.

Disadvantages – Timber cost, both for material and connection, are much higher than
the traditional structural materials of steel and concrete. Owing to its lesser material
strength, the member sizes would be very large and hence is not preferred for major
construction works. Durability and weathering of timber are other major issues.

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5.2 Diagrid Node Design

Fig. No. 5.1 Load Path at Node

The diagrid segments are planned to minimize onsite butt welding and the
welding locations illustrated in Figure 9. The load path can be divided into two main
scenarios,vertical load and horizontal shear their combination), as shown in Figure 8.
The vertical load will be transferred in the form of an axial load from the diagrid
members above the node to the gusset plate and stiffeners, then to the diagrid members
below the nodes as shown. The horizontal shear will be in the form of axial loads in the
diagrid members above the node with one in compression and one in tension to the
gusset plate and stiffeners. The force will then be transferred as shear force in the gusset
plate and then to the other pair of tensile and compressive forces on the diagrid
members below the node. From this load path, the shear force at the location of
bolt connections is high under lateral loads.Because this may create weak points at the
node particularly during earthquakes, the strength of the bolts should be designed
carefully.

Fig. No. 5.2 Node Design Plan

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5.2.1 Node Construction For Diagrid Structures

Constructability is a serious issue in diagrid structures because the joints of diagrid
structures are more complicated and tend to be more expensive than those of conventional
orthogonal structures. In order to reduce jobsite work, prefabrication of nodal elements is
essential. Due to the triangular configuration of the diagrid structural system, rigid
connections are not necessary at the nodes, and pin connections using bolts can be made m
ore conveniently at the jobsite. If considerately designed using appropriate prefabrication
strategy, constructability will not be such a limiting factor of the diagrid structures.
Prefabrication of diagrid nodes for conventional rectangular shape buildings can be done
relatively easily and economically because many nodes of the same configuration are
required in this case.
The Hearst Headquarters in New York is the typical case.

Fig. No.5.3 Node detail for the Hearst Tower

The
prefabricated nodes are connected to the large built-up diagonal members by bolts at the
jobsite. As building form becomes more irregular, generating appropriate construction modules
is critical for better constructability. Though it is possible to produce any complex shape
construction module using today’s CAD/CAM technology, it is not the most economical
solution. Extracting regularity from an irregular building form, and then adjusting the building
form following the extracted regularity could be one approach. Another approach could be to
make the construction modules relatively regular and design universal connections so that
they can accommodate any irregularity.

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Fig. No .5.4 A Diagrid node after fabrication

5.2.2
Erection of Diagrid Nodes
During construction, the stability in the in-plane direction can be provided by the modules
themselves and in the out-of-plane direction can be provided by the tie beams at the node. The
temporary restraint to the diagrid and the construction may be minimized. The various steps in the
Diagrid erection process include :

1) In-place steel shop welding

2) Lifting up piece by piece.
i)Trial shop assembly of parts with high strength bolts.
ii)In-place welding.
iii) High strength bolts assembly.
iv) Setting up perimeter girders

Fig. No. 5.5 Construction Plan of a Diagrid Fig. No. 5.6 Diagrid Erection Process

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Chapter 6

Case Study

Fig. No. 6.1 i-Lab Building, Hyderabad

Fig. No. 6.2 Interior view of i-Lab Building

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This prominent shell (55m x 23m x 21m) design is characterized by the use of a unique
diagrid structure used effectively to provide visual lightness and barrier-free usable office
spaces inside. The self-supporting form with minimal vertical supports lends the building `
an innovative look and reduces low life-cycle costs further. This five-storied pre-fabricated
lightweight structure took eight months for construction.The skin of the building is a
network of circular hollow M.S. sections with nodes that are welded during assembly. Steel
floor beams are spanned between the peripheral nodes and central ring beam and these
floor beams support the composite floor slabs. The core that houses the services has
columns of reinforced concrete with optimal and varying thickness of structural steel
usage.
Location:- Hyderabad
Client:- iLabs HTC Pvt Ltd
Architect:- Uday Joshi, Mumbai
Structural Consultant:- Construction Catalysers Pvt. Ltd.
Project Management Consultant:- Construction Catalysers Pvt. Ltd.
Software used:- Cad, 3D Max, Structural Softwares
Steel Producers:- Tata Structura
RCC Contractor:- Construction Catalysers Pvt. Ltd.
Steel Fabricator:- Construction Catalysers Pvt. Ltd.
Surface Protection (Painting etc):- Construction Catalysers Pvt. Ltd.
Electrical Contractor:- Construction Catalysers Pvt. Ltd.
Plumbing & Sanitary Contractor:- Construction Catalysers Pvt. Ltd.
Cost of project:- 12 Crore (For Steel Work)
Structural Steel requirement:- Not specified
Year of Commencement:- Jan-2008
Year of Completion:- Dec-2009

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Chapter 7
Results

7.1 Storey Displacement

There are G+24,G+36,G+48,G+60 storey wind and seismic analysis max.
displacement various diagrid angel and conventional building. As per IS 456-2000 in
clauses 23.2 page no. 37 permissible displacement should not exceed span/250.

Graph No. 1. G+24 Storey

Graph No. 2. G+36 Storey

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Graph No. 3. G+48 Storey

Graph No. 4. G+60 Storey

7.2 Storey Drift

There are G+24,G+36,G+48,G+60 storey wind and seismic analysis max.

displacement various diagrid angel and conventional buildingl. As per IS 1893(Part 1)-
2002 in clauses 7.11.1 page no. 27 permissible Storey Drift should not exceeds 0.004 times
the total height of the building.
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Study of a Multistory Building's Diagrid Structure

Graph No. 5 G+24 Storey Wind Analysis

Graph No. 6 G+24 Storey Seismic Analysis

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Graph No. 7 G+36 Storey Wind Analysis

Graph No. 8 G+36 Storey Seismic Analysis

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Graph No. 9 G+48 Storey Wind Analysis

Graph No. 10 G+48 Storey Seismic Analysis

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Study of a Multistory Building's Diagrid Structure

Graph No.11 G+60 Storey Wind Analysis

Graph No. 12 G+60 Storey Seismic Analysis

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7.3 Bending Moment

Graph No. 13 G+24 Storey

Graph No. 14 G+36 Storey

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Graph No. 15 G+48 Storey

Graph No. 16 G+60 Storey

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Chapter 8
Conclusion

8.1 General
The current study is carried out by considering the different angles of diagrid and also
different storey module of the varying building height. The proposed plan of 18m x 18m is
considered with four different types of angles of diagrid that is 57°, 63°, 69°,and 73° for 2
storey, 3 storey, 4 storey, 6 storey diagrid module for G+24, G+36, G+48 and G+60 storey
building. also comparative study diagrid and conventional building is carried out. We
conclude from the study that
 For all the 40 models consider for the study storey displacement and storey drift values
are within the permissible limit.
 Wind and seismic analysis are all storey diagrid angel 63° and 69° provides more
stiffeness to the diagrid structural system which reflect the less storey displacement, less
storey drift and less bending moment.
 Comparison of diagrid building and conventional building they are shows that diagrid
building are less displacement,less story drift and less bending moment in wind and
seismic analysis.
 Diagrid structure comparison to conventional building provide more aesthetic look it
becomes important for high rise structure
 So from result comparison with conventional building, one can adopt diagrid structure for
better lateral and gravitational load resistance.

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References

Journal Papers:

1. “ Study on diagrid structure of Multistorey building” Anjali Bhimrao Patil, Prof.

Dr.P.P.Saklecha, Prof. V.A.Kalmegh et.al. (2022).
2. “ Literature Review on Structural Role of Diagrids in High- Rise Structure under
Dynamic Forces” Vyankatesh Holambe, S. G. Ban, Syed Shafahaduddin Quadri et.al.
(2022).
3. “Study on diagrid structure of multistorey building” Ravi Sorathiya, Asst. Prof.
Pradeep Pandey et.al. (2017).
4. “ Diagrid Systems for Structural Design of Complex Shaped Tall Buildings” Kyoung
Sun Moon et.al. (2016).
5. “ Advantage of Steel Diagrid Building Over Conventional Building” Saket Yadav,
Dr. Vivek Garg et.al. (2015).
6. “Analysis and comparison of diagrid and conventional Structural system”
Raghunath .D. Deshpande, Sadanand M. Pati, Subramanya Ratan et.al. (2015).
7. “Analysis of tall buildings for desired angle of diagrids” Sree Harsha J, K Raghu, G
Narayana et.al. (2015).
8. “Comparative Study of Diagrid Structures with and without Corner Columns”
Shahana E, Aswathy S Kumar et.al. (2015).
9. “Analysis and Design of Diagrid Structural System for High Rise Steel Buildings”
Khushbu Jania , Paresh V. Patelb et.al. (2013).

Softwares:
STAAD.Pro v8i ss5 software.

Codes:

1. IS: 456-2000, “Indian Standard code of practice for Plain and Reinforced
concrete,”
Bureau of Indian Standards, New Delhi, India.
2. IS 875 (PART 3):1987 code for practice for design loads(other than earthquake) for
buildings and structures.
3. IS 1893 (part:1):2000 Proposed Draft Provisions and Commentary on Indian Seismic
Code.

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